splunk-security_content/docs/_posts/2020-07-06-windows_event_log_cleared.md

title, excerpt, categories, last_modified_at, toc, toc_label, tags

title	excerpt	categories	last_modified_at	toc	toc_label	tags
Windows Event Log Cleared	Indicator Removal on Host , Clear Windows Event Logs	Endpoint	2020-07-06	true		Indicator Removal on Host Clear Windows Event Logs Defense Evasion Defense Evasion Splunk Enterprise Splunk Enterprise Security Splunk Cloud

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Description

The following analytic utilizes Windows Security Event ID 1102 or System log event 104 to identify when a Windows event log is cleared. Note that this analytic will require tuning or restricted to specific endpoints based on criticality. During triage, based on time of day and user, determine if this was planned. If not planned, follow through with reviewing parallel alerts and other data sources to determine what else may have occurred.

• Type: TTP

• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

• Last Updated: 2020-07-06

• Author: Rico Valdez, Michael Haag, Splunk

• ID: ad517544-aff9-4c96-bd99-d6eb43bfbb6a

Annotations

ATT&CK

ID	Technique	Tactic
T1070	Indicator Removal on Host	Defense Evasion

| T1070.001 | Clear Windows Event Logs | Defense Evasion |

Kill Chain Phase

• Actions on Objectives

NIST

• DE.DP
• PR.IP
• PR.AC
• PR.AT
• DE.AE

CIS20

• CIS 3
• CIS 5
• CIS 6

CVE

Search

(`wineventlog_security` EventCode=1102) OR (`wineventlog_system` EventCode=104) 
| stats count min(_time) as firstTime max(_time) as lastTime by dest Message EventCode 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_event_log_cleared_filter`

Macros

The SPL above uses the following Macros:

• wineventlog_system
• security_content_ctime
• wineventlog_security

ℹ️ windows_event_log_cleared_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required field

• _time
• EventCode
• dest

How To Implement

To successfully implement this search, you need to be ingesting Windows event logs from your hosts. In addition, the Splunk Windows TA is needed.

Known False Positives

It is possible that these logs may be legitimately cleared by Administrators. Filter as needed.

Associated Analytic story

• Windows Log Manipulation
• Ransomware
• Clop Ransomware

RBA

Risk Score	Impact	Confidence	Message
70.0	70	100	Windows event logs cleared on dest via EventCode EventCode

ℹ️ The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

• https://docs.microsoft.com/en-us/windows/security/threat-protection/auditing/event-1102
• https://www.ired.team/offensive-security/defense-evasion/disabling-windows-event-logs-by-suspending-eventlog-service-threads
• https://attack.mitre.org/techniques/T1070/001/
• https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1070.001/T1070.001.md

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

• https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1070.001/atomic_red_team/windows-security.log
• https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1070.001/atomic_red_team/windows-system.log

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